Comment by Vladimir Mikulik (vladimir-mikulik) on Diagonalization Fixed Point Exercises · 2018-11-21T12:46:05.386Z · LW · GW

I’m confused about Q9.

Given the way $Syn(A,B)$ is defined, it’s unclear to me how we ensure type correctness of $Syn(S_1\times S_1,S_0)$. In what sense is $S_1\times S_1$ a set of sentences (rather than a set of pairs of sentences)? What does an element of that set look like?